This invention relates to a projectile launching attachment for use on an infantry weapon, such as a rifle, to permit the launching or firing of grenades.
Grenade launchers for use on infantry weapons are well known in the prior art. For example, U.S. Pat. No. 3,641,691 shows a grenade launcher with a pivotally mounted barrel supported beneath the normal rifle barrel of an M-16 type weapon. The launcher is intended to fire standard grenades from conventional cartridges.
U.S. Pat. No. 3,534,492 shows a grenade launching attachment for a firearm which is attached to the end of a conventional firearm barrel and propels the grenade with gas pressure from a blank round fired by the firearm.
Yet another approach to launching grenades using conventional infantry weapons is shown in U.S. Pat. No. 3,960,052 which shows a tripod mounted M-16 weapon firing a rocket propelled grenade from the weapon's barrel. The tripod mount utilizes the weapon in a mortar type arrangement where the grenade follows a high arc trajectory, rather than a more direct path, to its target.
None of the existing infantry weapon grenade launching arrangements are suitable for firing projectiles of the type shown in U.S. Pat. No. 3,610,091, for example, where the projectile has a hollow chamber at its rear end which has a propulsive charge loaded at the forward end thereof compressed by a piston which is backed by a guide rod on the launcher extending into the tube. Upon firing, the projectile is rapidly propelled from the guide rod as the projectile is rapidly accelerated relative to the guide rod. Although such projectiles have been utilized in various mortar type launchers where the launcher is supported against a ground surface and the projectile is fired in a high arc trajectory at a target, they have not been successfully shoulder fired.
Because the propulsive charge burns extremely rapidly, the firing of the projectile, including the movement of the piston from the top of the tube to the bottom, occurs in approximately two milliseconds. Because of the relatively high mass of the projectile and its warhead, the momentum transferred to the guide rod is quite large and, given its extremely short transfer time, the high perceived recoil has been unacceptably high, and has heretofore prevented use of this type of projectile in shoulder-fired or direct-held weapons not relying on a high arc trajectory, such as utilized with mortar type weapons.